The present invention relates to Christmas lights and more particularly to an internal sleeve in a double-lamp socket.
Convent Christmas light or a network reticulated with strings of Christmas lights are the structure of one socket with a single lamp that is somewhat too monotonous and can not present its beautification. Therefore, this structure of Christmas light is gradually going out of fashion. The applicant, faces up to such tendency, has filed several patent applications of one socket with two lamps for attempting to intensify the brightness and double-direction arrangement for the Christmas light. However, the double-direction arrangement may lead to parallel connection electric circuit that causes the reduction of the brightness for the lamps or that one of the lamps lightens and the other puts out. To improve this disadvantage, the electric circuit in the socket for two lamps should be in series connection which may keep the two lamps simultaneously lightened in same brightness. Besides, the contact plate in the socket should be stable to insure a perfect connection of the electric current.